1. Field of the Invention
The invention relates to an amplifier circuit, and more particularly to an ultra-wideband low-noise amplifier circuit for a radio frequency receiver.
2. Description of the Related Art
Due to development of wireless communication, demands for receiving/transmitting signals and data are growing. In conventional radio frequency receivers, an amplifier is often used as a first-stage component for reducing noise and amplifying signals. How to effectively promote gain of the amplifier and decrease power consumption is a primary goal in the industry.
A cascode amplifier is proposed in “A Ka-Band Low Noise Amplifier Using Forward Combining Technique; Yueh-Hua Yu; Wei-Hong Hsu; Chen, Y.-J. E; Microwave and Wireless Components Letters, IEEE; Volume 20, Issue 12; Digital Object Identidier: 10.1109/LMWC.2010.2085425; Publication Year: 2010; Page(s): 672-674”. In the forward combining technique proposed in this reference, precision of the phase shift cannot be achieved merely by a single inductor and a single resistor, leading to insufficient gain of the amplifier.
In addition, some conventional amplifiers use multiple power sources to promote gains thereof, which may lead to increased power consumption.